SAP: STORAGE AWARE PROTOCOLS FOR HETEROGENEOUS NETWORKSShweta Jain

Assistant Professor

Mathematics and Computer Science

York College CUNY

Outline• Background and Motivation

• Overview of network architectures• --Applications, Goals , Challenges and Proposed solutions

• Seamless communication

• Work in progress

• Next steps and future directions

BACKGROUND AND MOTIVATION

Arpanet in 1977

Source: The Computer History Museum ([1]), en:File:Arpnet-map-march-1977.png

Internet in 2010

Source: www.Caida.org

Some Statistics

• Mobile broadband users worldwide • 1.2 billion estimated by the ITU in 2011• Growth rate 45% annually over last 4 years• Mobile broadband subscriptions outnumber fixed subscriptions 2:1

• Top Mobile broadband Usage (survey 2010 by Keynote/Adobe)• Media and entertainment

• Social networking, (76%) local information (73%), news (68%), music (63%), games (61%), video (56%)

• Travel • Maps (81%), Research travel (47%)

Analysis of Usage• Users prefer to be mobile• People want their content NOW

• Mostly “Delay Intolerant” usage

• Delay tolerant applications – not so much?• Ebooks,. Podcast, etc

• Why do anything different with the delay tolerant traffic?

Google Search Trends – Wimbledon, Olympics, Podcasts and Ebooks

Wimbeldon

Olympics

Podcasts

eBooks

Analysis of Usage• Users prefer to be mobile• People want their content NOW

• Mostly “Delay Intolerant” usage

• Delay tolerant applications – not so much• ebooks,. Podcast

• Google trend shows searches including the terms ebooks and podcasts • Similar traffic all year round!

• Why do anything different with the delay tolerant traffic?• Need to make way for live streaming during the surge!• Historically when a service improves, demand for service also increases

and vice-versa

Key Motivation• Internet has evolved

• Needs new protocols for efficient delivery of content

• Mobile internet access is highly popular• Need a variety of mobile broadband infrastructures

• Mesh and Manet free/low cost services • Sensors, IoT, VANET secure, niche applications for utilities and services

• Need protocols that enable seamless communication across these networks

• Delay tolerant applications need to be served differently from “delay intolerant”• Podcasts, eBooks, sensors, Internet of Things create traffic all year

round

OVERVIEW OF NETWORK ARCHITECTURES

Applications, Communication Goals , Communication Challenges and Proposed solutions

Network Key Application Communication Goals

Communication Challenges

Proposed Solutions

Wireless mesh and MANET

Wireless and mobile communication in disaster zone, military, civilian settings

Provide peer-to-Peer, multicast, and broadcast communication

Load balancing, energy efficiency, fast routing updates

Distance vector, link-state and hierarchical routing protocols

Wireless sensor networks

Remote monitoring of the environmentForests, volcanos, buildings/home, war zone

Data aggregation from group/type of sensors rather than specific nodes

Prolong network lifetime by reducing communication overhead

In-network processing, local data aggregation

Internet of Things

Remote monitoring and control: smart grid, smart utility meters

Bi-directional communication between devices or groups

Communication Storm, ensure quality of service for time sensitive/mission critical applications

Several sensor network solutions are applicable

Network architecture research – Key points

Network Key Application Communication Goals

Communication Challenges

Proposed Solutions

Delay Tolerant Networks

Data delivery to remote areas:Rural areas, forest camp, army base,

Enable communication in networks that may not have end-to-end connectivity

Long periods of disconnection, no end-o-end route, traditional routing not applicable

Flooding, opportunistic transport, prediction based routing

Cognitive Radio Networks

Improve spectrum utilization:Public safety, military communication, consumer applications

Programmable radios communicating over licensed bands with minimum impact on primary users’ quality of service

Detect primary users, estimate spectrum availability and measure impact on primary user

spectrum sensing for user detection, database of primary user activity to predict spectrum availability

Network architecture research – Key points

Key Features• Routing technique:

• Control state or Data state based

• Cost metrics:• Link cost or Historical connectivity information

• Transport• End-to-end TCP/UDP or Opportunistic transport, send data as

soon as a candidate forwarding node is available•

•

SEAMLESS COMMUNICATIONStorage aware protocols (Network and Transport)

Key Observations• From an application standpoint:

• All networks are in general prone to varying degree of disconnections

1) Mobile devices lose connectivity for long or short time periods

2) Mobility triggers new route discovery, causing disconnection until a new end-to-end path is discovered

3) Sensor networks re-configure routes to avoid network partition due to battery depletion

4) IoT are struggling with communication storms which may be inferred as disconnection by the application

5) Cognitive radios stop transmitting when a primary user is detected

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Generalized Delay Tolerant Networks: gDTN

• Observation:• In general all network architectures have properties similar to the Delay

Tolerant Networks

• Wireless characteristics• Intermittent connectivity – Cognitive Radio, MANET, VANET• Variable link speed – Bluetooth, WiMAX, WiFi, Cellular Internet• Long term disconnection – Mobility• Every vertical handoff changes the link speed

• These are similar to Disruption Tolerant network (DTN) features• DTN is the extreme case of challenged networks• Wired is the other extreme case of well provisioned networks • Other wireless networks are somewhere between this red and

green

gDTN: Generalized DTN• ??:

• Can a storage and prediction based approach be the one-size fit all solution to the problem of seamless interconnection?

• Can we combine features of wireless routing with history and storage based DTN routing?

• Proposal• SAP: Storage Aware Protocols for seamless integration of

heterogeneous network architectures

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WORK IN PROGRESSStorage Aware Protocols (SAP)

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Components of SAP• Storage Aware Routing (STAR)

• Use history based routing metric• Use storage to delay data delivery while the network searches for

“better” pathsBetter ϵ {Energy efficient, most storage, fastest, higher probability of success,…}

• Disruption tolerant transport • End-to-end transport with proxy and feedback for disconnection

STAR: Storage Aware Routing• Compute multiple paths to the destination using the hop count based routing

metric- breadth first topology search• Maintain long and short term “expected link rates” to describe the

temporal/variable cost component of the routes• Choose to store when the best path is

• Worse than usual or • Downstream routers have low available storage (network layer

backpressure flow control)

(Future routers will have storage space for caching and temporary storage) (storage is getting cheaper by the year)

Forwarding Algorithm

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Storage Router

Applicable to all networks?• Applicability:

• Long term cost: Time scale of variation depends upon the network type

• Storage space: Indicates congestion in wired, wireless, DTN (congestion is a measure of storage space)

• Storage aware routing concept for all networks• Unifies and generalizes the routing scheme across

networks• Support for mobility • Allows policy and price based store or forward

• Avoid expensive 3G • Store if the Wi-Fi data rate is lower than usual

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End to End Transport• Send feedback to sender or sender’s agent when data

forwarding is interrupted• Sender keeps the route alive by sending 1 byte packets– similar to

flow control in TCP• Data is stored at the last router that detected disconnection• If route becomes available, transmission resumes• If it takes too long….

• The end host will need to retry

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NEXT STEPS AND FUTURE DIRECTIONS

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Next Steps• Implementation and evaluation

• Simulation and emulation of network and transport on wired-wireless mesh and DTN testbeds

• Tying the lose ends• How much state to maintain?• Proxy placement• How long and how much to store?

Future Directions• Integration of networks is necessary but difficult

• Several lose ends and unanswered questions

• Security, data integrity and privacy

THANKS FOR LISTENING!Questions and feedback please?